Post-hole digger.



I S. E. BROOMALL.

POST HOLE BIGGER.

APPLICATION FILED JULY 12, 1911.

Patented June 25, 1912.

3 SHEETS-SHEET 1.

ammo/0M0 L'GLUMIHA PLANOGRAI'H cu., WASHINGTON, n. c.

nrren.

SAMUEL E. BROOMALL, 0F WILMINGTON, DELAWARE.

POST-HOLE BIGGER.

Specification of Letters Patent.

Application filed July 12, 1911.

Patented June 25., 1912. Serial No. 638,195.

To all whom it may concern:

Be it known that I, SAMUEL E. BROOMALL, a citizen of the United States, residing at Wilmington, in the county of Newcastle, State of Delaware, have invented certain new and useful Improvements in Post-Hole Diggers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to post hole diggers, and has for an object to provide a drill mounted for combined reciprocating and rotary movement in a suitable frame, a rack and pinion connection with the motive power serving to sink the drill and also to lift the drill, novel means being employed for automatically stopping and locking the drill stationary at a predetermined position in its lifting movement.

A further object of the invention is to provide a novel brake mechanism for controlling the sinking movement of the drill.

With the above objects in view the invention consists in certain novel. details of con struction and combination of parts hereinafter fully described and claimed, it being understood that various modifications may be made in the minor details of construction within the scope of the appended claims.

In the accompanying drawings forming part of this specification :Figure 1 is a side elevation of a post hole digger embodying my improvements. Fig. 2 is a side elevation of the post hole digger. Fig. 3 is a longitudinal sectional vieu with parts in elevation. Fig. 4 is a plan view of the post hole digger. Fig. 5 is a cross sectional view taken through the drill chuck on the line 5 5 Fig. 1. Fig. 6 is a cross sectional view taken through the drill shank on the line 66 Fig. 1.

Referring now to the drawings in which like characters of reference designate similar parts, 10 designates an inverted ll-shaped frame, the legs of which are connected at their lower ends by a bridge bar 11. The arched top of the frame is provided centrally with an enlargement 12 which is formed with an approximately square open ing 13 which receives a vertically disposed rack bar 1 1. The lower end of the rack bar is equipped with an approximately pyramidal shaped chuck 15 formed in two pieces 16 and 17, the pieces being bolted or otherwise secured together as shown at 18. A suitable rabbet 19 is formed in the top face of the chuck to receive the end of the rack bar, the latter being bolted or otherwise rigidly secured to the chuck as shown at 20.

The bottom face of the chuck is provided with a cylindrical rabbet 21 which is internally provided with an annular stop shoulstem 28 of a drill point 29, pins 30 being passed through the stem and socket member to removably secure the point to the drill shank.

The drill shank is designed to be rotated for advancing the drill point into the earth, and to attain this end a bevel gear 31 is fitted to the shank, and is provided with an internal tongue 32 which fits in a longitudinal groove 33 formed in the drill shank, this construction permitting of' the drill shank sliding through the gear while being rotated by the latter. A horizontally disposed driving shaft 34 is journaled in suitable bearings formed in one side of the frame and in an upstanding lug 35 disposed on the bridge bar, and is equipped with a bevel gear 36 which meshes with the bevel gear 31, and maintains the latter bearing against the bridge piece at all times. The driving shaft is equipped with a driving pulley 37 which may be operatively connected to any desired motive power. The driving shaft further extends through the bearing in the frame, and. is equipped at its outer end with a loose pulley 38 and is further equipped with a fixed pulley 39 intermediate the loose pulley and side of the frame. The fixed pulley forms means for reciprocating the rack bar for sinking or elevating the drill as will now be described.

Rising from the arched top of the frame are spaced orificed lugs 40 in which is journaled a horizontally disposed shaft 41, which is equipped intermediate the lugs with a pinion 42 that meshes with the teeth on the rack bar. One end of the shaft projects through one of the lugs, and is equipped at its outer end with a loose pulley 43, and is further equipped with a fixed pulley 44 intermediate the loose pulley and lug, these pulleys alining with the corresponding loose' and fixed pulleys on the driving shaft. An endless belt 45 is trained over one pair of the pulleys, and is capable of being manually shifted to the opposite pair by means of a right angular shifting lever 46 which is pivoted centrally of one of its legs to the side of the frame as shown at 47, the lever being equipped with the usual slotted free leg 48 which embraces the belt. When the belt is shifted to the fixed pulleys, the rack bar, during rotation of the driving shaft in one direction,will be moved downward through'the instrumentality of the pinioni42, while at the same time the drill shank 23 will be reciprocated, and in this manner the drill point is sunk into the earth. When a hole of the desired depth has been made, the motive power may be actuated to rotate the driving shaft in the opposite direction, whereupon the rack bar will be elevated through the instrumentality of the pinion 42, and simultaneously rotate the drill shank in the opposite direction and withdraw the same from the hole.

For automatically controlling the elevating movement of the drill, a bell crank shifting lever 49 is pivoted at its elbow by a pivot pin 50 to one side of the frame, one leg of the lever being equipped with an offset slotted arm 51 which embraces the belt,

and the opposite leg of the lever being of such length as to extend a little beyond the vertical central diameter of the chuck, this leg normally bearing upon the upper side of a lug 52 which projects from one side of the chuck. During elevating movement of the chuck, the lug will elevate this leg of the bell crank shifting lever thereby rocking the lever on its pivot and movingthe belt embracing arm of the lever outwardly to such an extent as to shift the belt from the fixed pulleys to the loose pulleys when the chuck has risen to nearly the top of the frame as clearly shown in Fig. 1. The actuating rack bar is automatically locked at its upper limit of movement as will presently be described when the belt has been shifted from the fixed to the loose pulleys so that the drill will be held against gravitating. Upon releasing this locking means, the chuck will gravitate, it beingunderstood that the frame is mounted upon a vehicle or similar support that elevates the point of the drill considerably above the earth when the chuck is in itshighest limit of movement. Upon gravitating movement of the chuck, the chuck engaging leg of the bell crank shifting lever will fall down with the chuck until the lever assumes the position shown in dotted lines in Fig. 1, whereupon the manually operatable shifting lever may be actuated to shift the belt back onto the fixed pulleys for sinking the drill as above described.

The rack bar locking means consists of a horizontally disposed stub shaft which is journaled in suitable bearings formed in outstanding lugs 54 and arranged on the arched top of the frame. One end of the shaft projects beyond the outermost bearing and is equipped with a weighted lever 56. The shaft is further equipped withan approximately V-shaped pawl 57, one leg of' the pawl being rigidly fixed to the shaft, and the other leg of'the pawl being adapted to lockingly engage in a recess 58 formed in the rear face of the rack bar, this recess being so positioned that the working leg of the pawl slips into the recess at the moment when the bell crank shifting lever is operated to shift the belt from the fixed to the loose pulleys. In this manner the rack bar is locked at its upper limit of movement and will remain in this position until the weighted lever is manually lifted.

For controlling the reciprocating movement of the drill when working in various soils such as rocky. soil, sand, gravel and the like, a brake pulley 58 is fixed to the shaft 41, and a band brake 59 is trained over the pulley, one end of the band brake being fixed in a standard 60 arranged on the arched top of the frame, and the opposite end of the band being equipped with a link 61 which extends downwardly through the frame, and is equipped at its lower end with a pivoted treadle 62. Upon depression of the treadle, the band will be moved into tight frictional engagement with the brake pulley, and the speed of the shaft 41 slowed up as is obvious.

What is claimed, is

1. A post hole digger including a frame, a drill mounted for combined rotary and reciprocating movement on said frame, means for reciprocating said drill, means for manually controlling sliding movement of said drill in one direction, means for automatically stopping said reciprocating means upon a predetermined sliding movement of said drill in an opposite direction, and means for automatically locking said drill in stationary position after the last named means has operated.

2. In a post hole digger, a frame, a drill mounted for combined revoluble and reciprocating movement on said frame, means for rotating said drill, means for reciprocating said drill, an operative connection coupling said means for simultaneous actuation, a bell crank shifting lever pivoted on said frame and operatively connected to said coupling means and to said drill, said lever operating to move said coupling means out of operative position during sliding movement of said drill in one direction to a predetermined position, and means locking said drill against reciprocating movement after said lever has operated.

3. A post hole digger including a frame, a drill mounted for combined rotary and reciprocating movement on said frame, a driving shaft operatively connected to said drill for rotating the drill, a rack forming an extension of said drill, a driving shaft operatively connected to said rack for reciprocating the rack, juxtaposed loose and fixed pulleys on both shafts, a belt selectively engageable with corresponding pulleys on said shaft, a manually operatable means for shifting said belt, an angular bell crank shifting lever pivoted on said frame and having one leg operatively engaging said drill, said drill rocking said bell crank lever on its pivot whereby to shift said belt to said loose pulleys upon movement of said drill in one direction to a predetermined position, and a Weighted pawl automatically locking said rack stationary after said bell crank lever has operated.

In testimony whereof, I affix my signature, in presence of two witnesses.

SAMUEL E. BROOMALL. WVitnesses:

"WILLIAM BULLOCK,

JOHN BULLOCK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner o1 Patents. Washington, D. C. 

